The Government has called for tenders to search for minerals in Northland.
Data gathered from an aeromagnetic survey of more than 13,500 square km of land indicated significant quantities of copper could lie underground in Northland, along with deposits of gold, silver, zinc, antimony and lead.
Three areas of the region have been mined for copper in the past.
Under the tenders, minerals exploration companies have six months to evaluate the data and submit five-year exploration schemes.
Successful applicants are expected to be announced in early April next year.